The present invention relates to apparatus for measuring pulse energy, the apparatus including integration means and serving to measure high-current disturbances carried by a cable. The present invention applies in particular to measuring energy from disturbances carried by a grounding cable via protection equipment, and as caused by lightning or of electromagnetic origin, especially with a view to monitoring such equipment.
Various types of protection equipment for providing protection against disturbances caused by lightning or of electromagnetic origin are known per se, e.g. lightning arresters or circuits or apparatus for protecting power lines, installations, or appliances. Such equipment is provided with a grounding cable for carrying the current due to each disturbance to ground. Such disturbances are of relatively low frequency, and not more than about 1 MHz to 2 MHz. The current due to such disturbances is high, its maximum value may vary from one disturbance to another, and said maximum value may be about one hundred kiloamperes.
To make the protection provided by such equipment reliable, it is useful to have information giving the stresses on each item of protection equipment, so as to make it possible to determine the effectiveness of the equipment or to estimate its operating state at any given time and its probable life span, and to perform the appropriate maintenance operations.
To that end, lightning pulse counters are known that count the disturbances received and that increment a display by unity each time a new disturbance is received. Unfortunately, such counting is only a very inaccurate reflection of the real stresses on the protection equipment in question.